JPH05185670A - Platen for printer - Google Patents

Abstract

PURPOSE:To miniaturize a printer and to reduce the wt. and noise thereof by reducing the number of components by simplifying the drive components of a platen and also reducing the number of processes in assembling adjustment. CONSTITUTION:A platen rotor 12 feeds paper sheets and is journaled on a frame 2 in a freely rotatable manner. A stator shaft 10 is provided with a resonator 10a rotating the platen rotor 12 and arranged in the platen rotor 12. A piezoelectric element 11 receives an ultrasonic electric signal to vibrate the resonator 10a to rotate the platen rotor 12 and an encoder consisting of a slit plate 6 and a photointerruptor 7 detects the angle of rotation of the platen rotor 12. A tension bracket 3 fixes one end of the stator shaft 10 and a tension spring 4 whose energizing force is changed by an adjust nut 5 is provided and the contact of the resonator 10a with the platen rotor 12 is regulated by bending the stator shaft 10 by changing the energizing force of the tension spring 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a platen for a printer device which is directly driven by vibration of ultrasonic waves.

[0002]

2. Description of the Related Art Platen 21 for a conventional printer device
As shown in FIG. 3, the stepping motor 16, the pinion gear 17, and the intermediate gear 1 attached to the frame 20
8, driven by the feed gear 19 and the like. In addition,
The stepping motor 16 is a drive source, and rotates the platen 21 via the pinion gear 17, the intermediate gear 18, and the feed gear 19.

As another driving means, although not shown, pulleys are attached to the motor and the platen respectively, and a timing belt or the like is arranged between the pulleys.

[0004]

The above-mentioned conventional platen 21 has a large number of parts and is complicated, and the number of steps for assembling and adjusting is also complicated. Further, since a motor and a gear are used, there is a limit to reduction in size and weight, and there is a problem that mechanical noise is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a platen for a printer device which is simple and has a small number of parts to reduce the number of steps for assembling and adjusting, and enables the device to be compact and lightweight. To aim.

[0006]

In order to achieve the above object, the present invention according to claim 1 conveys a sheet and rotates a platen rotor rotatably supported by a frame. A stator part that is located inside the platen rotor and is fixed to the frame; and an ultrasonic electric signal is input to vibrate the resonator to rotate the platen rotor and to rotate the stator part. And a rotation angle detector for detecting the rotation angle of the platen rotor. In addition, claim 2
According to the present invention, the stator section is a stator shaft, the rotation detecting section is an encoder including a slit plate provided at one end of the platen rotor and a photo interrupter provided at the frame, and one end of the stator shaft is provided. It is equipped with a tension bracket that has a tension spring that can be fixed and whose urging force can be changed by an adjusting nut.The urging force of the tension spring can be changed by the adjusting nut and the stator shaft can be deflected to bring the resonator into contact with the platen rotor. Is configured to adjust.

[0007]

In the present invention according to claim 1 configured as described above, when an ultrasonic electric signal is input to the piezoelectric element,
Vibrate the resonator. The vibrating resonator causes the platen rotor to rotate. The rotation angle of the platen rotor is detected by the rotation angle detector. Further, in the present invention according to claim 2, the biasing force of the tension spring is changed by the adjusting nut. The change in the biasing force causes the tension bracket to bend, and the stator shaft fixed to the flexure bracket also moves to adjust the contact between the resonator and the platen rotor. Further, the slit plate rotates in the photo interrupter to detect the rotation angle of the platen rotor.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a printing apparatus provided with a platen 1 of this embodiment. This printing apparatus is provided with a lever 17 for moving a thermal head 16 and a feed knob 18 for feeding thermal paper sheets on one side of the frame 2. Further, on the other side of the frame 2, a tension bracket 3, a tension spring 4, an adjusting nut 5, a slit plate 6, a photo interrupter 7, etc. are provided.

The tension bracket 3 fixes the end of the stator shaft 10 and locks one end of the tension spring 4. The adjusting nut 5 changes the biasing force of the tension spring 4. The slit plate 6 is provided at the end portion of the platen rotor 12, and detects the rotation angle of the platen rotor 12 together with the photo interrupter 7.

Further, as shown in FIG. 2, the platen 1, which is a characteristic part of the present invention, has a cylindrical platen rotor 12 having a platen rubber 13 on its outer periphery, and the platen rotor 1.
2 and the stator shaft 10 located inside.

The platen rotor 12 is rotatably supported by the frame 2 via a sliding bush 2a. Also,
The stator shaft 10 includes a piezoelectric element 11 and a resonator 10a.
And are provided. The piezoelectric element 11 receives a signal having a high amplitude and a frequency in the ultrasonic range from an ultrasonic electric signal generating section controlled by a control section of a printing device (not shown), and self-oscillates to vibrate the resonator 10a. It is a thing. The resonator 10a is in contact with the inner peripheral surface of the platen rotor 12. Further, the degree of contact between the resonator 10a and the platen rotor 12 is determined by the degree of force exerted on the resonator 10a by the deflection force of the tension spring 4 caused by the adjusting nut 5 to flex the tension bracket 3 as appropriate. ..

Next, the operation of the platen 1 will be described. When a signal having a high amplitude and a frequency in the ultrasonic region is supplied from the ultrasonic electric signal generator (not shown) to the piezoelectric element 11, the phase of time and position shown by the following formula (1) is different by 90 degrees. A two-phase standing wave is excited. By superposing this standing wave, progressive elastic bending vibration (traveling wave) represented by the following equation (2) is generated in the stator shaft 10. sin (ωt) × cos (θr2π / λ) -cos (ωt) × sin (θr2π / λ) ··· (1) formula = sin (ωt-θr2π / λ) ··· (2) formula

Focusing on the movement of the resonator 10a that is in close contact with the platen rotor 12, as the traveling wave progresses,
The resonator 10a draws an elliptical orbit by combining vertical movement due to bending of the traveling wave and rotational movement due to expansion and contraction. The adjustment nut 5 is rotated to change the biasing force of the tension spring 4 to move the tension bracket 3, and the resonator 10a is brought into pressure contact with the platen rotor 12, so that the movement of the apex portion of the elliptical orbit described above is performed. Convert to the rotational motion of. The rotation of the platen rotor 12 feeds the thermal paper sheets.

The platen rotor 12 is composed of a slit plate 6 and a photo interrupter 7, which are so-called encoders.
Of the rotation angle of the printer is detected and output to the control unit of the printer device (not shown). Then, this control unit appropriately changes the electric signal to the piezoelectric element 11 based on the input data to control the rotation angle and speed of the platen rotor 12.

[0015]

As described above, according to the present invention, the platen rotor is rotated by supplying ultrasonic electric signals to the piezoelectric element and the resonator provided inside the platen rotor to vibrate them. Therefore, the driving parts of the platen are simplified, the number of parts is reduced, the man-hours for assembling and adjusting are also reduced, and it is possible to reduce the size and weight of the printer device and reduce the noise.

[Brief description of drawings]

FIG. 1 is a plan view of a printer device using a platen of this embodiment.

FIG. 2 is a sectional view of a main part of the platen of the same.

FIG. 3 is a plan view of a printer device using a conventional platen.

[Explanation of symbols]

 1 Platen 2 Frame 3 Tension Bracket 4 Tension Spring 5 Adjustment Nut 6 Slit Plate 7 Photointerrupter 10 Stator Shaft 10a Resonator 11 Piezoelectric Element 12 Platen Rotor

Claims (2)

[Claims] 1. A platen rotor that conveys paper sheets and is rotatably supported by a frame, and a resonator that rotates the platen rotor. The platen rotor is located inside the platen rotor and is fixed to the frame. A stator section, a piezoelectric element provided in the stator section for rotating the platen rotor by vibrating the resonator by inputting an ultrasonic electric signal, and a rotation angle detecting section for detecting a rotation angle of the platen rotor. A platen for a printer device, which is configured by: 2. The stator section is a stator shaft, and the rotation detecting section is an encoder including a slit plate provided at one end of the platen rotor and a photo interrupter provided at the frame, and one end of the stator shaft is fixed. The tension bracket is provided with a tension spring whose urging force can be changed by the adjustment nut.The urging force of the tension spring is changed by the adjustment nut, and the stator shaft is deflected to bring the resonator into contact with the platen rotor. The platen for a printer device according to claim 1, wherein the platen is adjusted.